Abstract: An object of the present invention is to provide a hybrid welding method which can improve the stability of the arc, the welding speed, and welding efficiency, and the present invention provides a hybrid welding method in which a TIG arc is generated on the front side in the welding direction, and a MIG arc is generated on the back side in the welding direction in order to weld a welding base material, wherein electric current for the TIG welding is larger than electric current for the MIG welding; and an absolute value of the interval between an intersection of a center axis of a TIG electrode and a surface of the welding base material and an intersection of a center axis of a MIG electrode and the surface of the welding base material is 4 mm or less.

Abstract: This disclosure relates generally to welding, and more specifically, to submerged arc welding (SAW). In an embodiment, a welding system includes a gas supply system configured to provide a gas flow. The system also includes a wire supply system configured to provide welding wire, and a flux supply system configured to provide flux near a welding arc during submerged arc welding (SAW). The system further includes a welding torch assembly configured to receive the gas flow and the welding wire and to deliver the gas flow and the welding wire near the welding arc during SAW.

Abstract: Weld metals and methods for welding ferritic steels are provided. The weld metals have high strength and high ductile tearing resistance and are suitable for use in strain based pipelines. The weld metal contains retained austenite and has a cellular microstructure with cell walls containing lath martensite and cell interiors containing degenerate upper bainite. The weld metals are comprised of between 0.02 and 0.12 wt % carbon, between 7.50 and 14.50 wt % nickel, not greater than about 1.00 wt % manganese, not greater than about 0.30 wt % silicon, not greater than about 150 ppm oxygen, not greater than about 100 ppm sulfur, not greater than about 75 ppm phosphorus, and the balance essentially iron. Other elements may be added to enhance the properties of the weld metal. The weld metals are applied using a power source with current waveform control which produces a smooth, controlled welding arc and weld pool in the absence of CO2 or oxygen in the shielding gas.

Abstract: An installation for welding top plugs on to nuclear fuel rods comprising a device for axially holding said rod and setting it in rotation and a weld chamber, where said device comprises a gripper and means to close the gripper on the rod, where said means comprise a pusher to apply an axial force on to the gripper, a linear actuator of axis parallel to the lengthways axis of the device, a yoke translationally secured to said pusher, and able to rotate freely around a fixed axis orthogonal to the lengthways axis which is not secant with the latter, where said yoke is connected and able to pivot relative to the linear actuator around a fixed axis parallel to the orthogonal axis such that the linear actuator causes the yoke to rotate around the first orthogonal axis and causes the pusher to slide, closing the gripper on the rod.

Abstract: An attachment system, for attaching a gas nozzle on a gas nozzle mount arranged on a welding torch, allows detachable attachment of the gas nozzle. To create such an attachment one part of the gas nozzle mount is designed to be eccentric and for mounting a fixing element. Via an additional part of the gas nozzle mount and via at least one part of a penstock of the welding torch, a guide is formed for the gas nozzle and the gas nozzle can be secured via a rotational movement.

Abstract: The constricting nozzle of the present invention includes (i) a cylindrical nozzle body disposed around the forward end of the tungsten electrode rod concentrically with the tungsten electrode rod and defines an annular high-speed gas passage between the nozzle body and the outer peripheral surface of the forward end of the tungsten electrode rod, (ii) a plurality of positioning projections that are protrudently formed on the inner peripheral surface of the nozzle body with predetermined intervals in the circumferential direction and that are arranged along the longitudinal direction of the nozzle body to hold the tungsten electrode rod in the center position of the nozzle body, and (iii) a plurality of gas-flow regulating grooves formed between the positioning projections and that extend in parallel in the longitudinal direction of the nozzle body and regulate the shielding gas (G) flowing through the high-speed gas passage.

Abstract: Various welding systems including a welding torch assembly are provided. The welding torch assemblies may include a welding torch adapted to be utilized in a welding operation to establish a welding arc between the welding torch and a workpiece. The welding torch assemblies may also include a temperature sensing system integral with the welding torch and adapted to sense a temperature of the workpiece.

Abstract: A method for protecting a work piece for use in abrasive environments with hardbanding is provided. The layer is deposited onto at least a portion of the work piece to be protected. The deposited layer exhibits a hardness of at least 50 Rc, a wear rate of less than 0.5 grams of mass loss as measured according to ASTM G65-04, Procedure A, a wear rate on a contacting secondary body comprising carbon steel of less than 0.005 grams as measured according to modified ASTM G77 wear test. The deposited alloy forms an iron matrix comprising embedded hard particles in an amount of less than 15 vol. %. The embedded hard particles have an average particle size of ranging from 100 nm to 5 ?m. In one embodiment, the deposition is via welding.

Abstract: An apparatus for forming electrical solder connections in a disk drive unit includes: a nozzle device for carrying out soldering on two pre-welding surfaces; a solder ball feeding device for transferring a single solder ball to the nozzle device; a gas pump device for supplying pressurized gases to the nozzle device; a laser device for emitting laser beams to the solder ball,; and a control device including at least one sensor for at least detecting status of the solder ball or pressure in the nozzle device or distance between the nozzle device and the pre-welding surfaces, and a control unit connected with the at least one sensor. The present invention can easily control the solder ball, the pressurized gases and the laser beams, thereby keeping the pressure of the nozzle device and the laser energy stable and, in turn improving the soldering result.

Abstract: This disclosure relates generally to welding, and more specifically, to submerged arc welding (SAW). In an embodiment, a welding system includes a gas supply system configured to provide a gas flow. The system also includes a wire supply system configured to provide welding wire, and a flux supply system configured to provide flux near a welding arc during submerged arc welding (SAW). The system further includes a welding torch assembly configured to receive the gas flow and the welding wire and to deliver the gas flow and the welding wire near the welding arc during SAW.

Abstract: A method of joining at least two components, a method of preventing erosion of a base component and a turbine blade is provided. The method of joining at least two components includes providing a laser cladding apparatus, aligning a first component and second component, and jointing the first and second components by laser cladding. The first component includes a first joining surface adjacent to a seconding joining surface of the second component. The first joining surface and the second joining surface are joined by laser cladding along a joining plane. A joining material from the laser cladding provides at least one joining layer between the first joining surface and the second joining surface. The first and second joining surfaces include a bevel angle. A method for rendering a component resistant to erosion and a turbine blade are also provided.

Abstract: There is provided a flux-cored wire containing flux within a stainless steel or mild steel outer cover for use in stainless steel welding and gas-shielded arc welding using a shielding gas. The flux-cored wire contains, based on the total mass of the flux-cored wire, predetermined amounts of C, Si, Mn, P, S, Cr, Ti, and O. The remainder are Fe and incidental impurities. The shielding gas is pure Ar gas.

Abstract: In a tandem gas-shielded arc welding method, carbon dioxide is used as a shielding gas for a leading electrode formed by a solid wire, an argon-carbon dioxide gas mixture containing at least 60% by volume of argon gas is used as a shielding gas for a trailing electrode formed by a solid wire or a flux-cored wire, both the leading electrode and the trailing electrode have a reverse polarity, the leading electrode satisfies the relationships “5.00?(I·V·10?8)/(Wf·?r2)?10.00” and “(I2·10?3)/V?4.50”, and the trailing electrode satisfies the relationships “4.00?(I·V·10?8)/(Wf·?r2)?7.00” and “(I2?10?3)/V?8.00”.

Abstract: Purge gas apparatus and method for a welding system uses automatic purge gas flow control function, such as an MFC, to control ID and/or OD purge gas flow rate or purge gas pressure or both at the weld site.

Abstract: Apparatus and method for controlling blanket gas flow in an electrical welding facility, wherein welding is performed using a welding electrode in electrical connection with a welding machine unit. The apparatus includes an electric measuring device having a current sensor for determining the magnitude of an electrical welding current carried in a circuit incorporating the welding electrode and having a current sensor output adapted to provide a I signal indicating the current magnitude, and a voltage sensor for determining the magnitude of electrical voltage applied to the welding electrode and having a voltage sensor output for providing a U signal indicating the voltage magnitude, and a control device having inputs connected to the current sensor output and the voltage sensor output, respectively, and a control signal output for providing a control signal to a blanket gas flow controller.

Abstract: A system and method is provided in which each of a GMAW power supply and a TIG/plasma power supply are utilized in a common weld joint, where the waveforms from each of the power supplies are pulsed waveform which are pulsed out of phase which each other. Such a system minimizes arc interference and arc blow while at the same time increasing travel speed and throughput of a welding operation.

Abstract: Shaped metal deposition apparatus comprises a mounting head for mounting a shaped metal deposition device, an inert gas shield for providing an inert atmosphere around shaped metal deposited in use by the shaped metal deposition device, and a rotatable coupling between the mounting head and the inert gas shield to permit relative rotation therebetween.

Abstract: A method of roll-forming sheet or plate into a round hollow, welding the round hollow with a welding alloy that matches the alloy of the round hollow to form a welded pipe, annealing the welded pipe at a minimum of 1950° F. to provide a carbide-free microstructure, ultrasonic inspecting to assure sound welds, and cold-working the annealed and inspected pipe via drawing or pilgering to the desired tensile strength. The compositional range alloys suitable for use in the method of the present invention in weight % is: 25.0-65.0% Ni, 15.0-30.0% Cr, 0-18.0% Mo, 2.5-48.0% Fe, 0-5.0% Cu, 0-5.0% Mn, 0-5.0% Nb, 0-2.0 Ti, 0-5.0% W, 0-1.0% Si, and 0.005-0.1% C. The process has been most preferably optimized for an alloy range consisting of 32.0-46% Ni, 19.5-28.0% Cr, 18.0-40.0% Fe, 3.0-8.0% Mo, 1.0-3.0% Cu, 0.6-1.2% Ti, 0.5-2.0% Mn, 0.1-0.5% Si, 0.01-0.08% C. The present invention also includes the pipe made thereby.

Abstract: A submerged arc welding apparatus of the present invention includes: a flux receiver for receiving and holding flux in an area formed by itself and a workpiece inside thereof when abutting against the workpiece on the open side; a flux feeder for supplying flux to the flux receiver; a welding torch for supplying a welding wire toward the workpiece with the tip disposed in the area where the flux is held; and a moving mechanism for moving the flux receiver and the welding torch along the direction of a welding line of the workpiece with the flux receiver abutting against the workpiece. A submerged arc welding method of the present invention includes: performing welding by opposing the welding torch to the workpiece and by moving the welding torch along the direction of the welding line with flux held in an area formed between the workpiece and the welding torch.

Abstract: The invention relates to a twin wire welding apparatus (1) including a first contact tube (2) for guiding a first consumable electrode (4) toward a weld puddle (6) and transferring welding current to the first consumable electrode (4), a second contact tube (10) for guiding a second consumable electrode (12) toward said weld puddle (6) and transferring welding current to the second consumable electrode (12), and a single power source (16) connected to said first and second contact tubes (2,10) for providing the same potential to said two consumable electrodes (4,12), and to a method for operating such an apparatus.

Abstract: A welding system having a welding gun with a contact tip having an bore extending therethrough and a consumable weld wire. The cross-sectional shape of the bore of the contact tip being is essentially identical to the cross-sectional shape of the weld wire. The bore having an essentially elliptical cross-sectional shape and the weld wire having an essentially elliptical cross-sectional shape.

Abstract: A welding method, which performs non-keyhole welding of a ferritic stainless steel having a plate thickness of 3 mm or less using a plasma welding torch (10), includes supplying an inert gas, as a pilot gas (23), into the gap between a tungsten electrode (11) and an insert chip (12) at a flow rate of 2.1 m/sec or less, and supplying a shield gas (24) into the gap between the insert chip (12) and a shield cap (15), wherein a mixed gas prepared by adding either 0.5 to 4 vol % of oxygen gas or 1 to 6 vol % of carbon dioxide gas to an inert gas is used as the shield gas (24).

Abstract: A method of forming an optical device comprises applying a laser beam to a target area of the surface so as to selectively heat material of the surface thereby to provide transfer of material due to a surface tension gradient, wherein the surface is such that, when liquid, parts of the surface at higher temperatures have a higher surface tension than adjacent parts of the surface at lower temperatures.

Abstract: The present invention relates to a system and method for automated or “robotic” application of hardfacing to the surface of a steel-toothed cutter of a standard earth-boring rock bit or a hybrid-type rock bit. In particular, the system incorporates a grounded adapter plate and chuck mounted to a robotic arm for grasping and manipulating a rock bit cutter, particularly a hybrid rock bit cutter, beneath an electrical or photonic energy welding source, such as a plasma arc welding torch manipulated by a positioner. In this configuration, the torch is positioned substantially vertically and oscillated along a horizontal axis as the cutter is manipulated relative along a target path for the distribution of hardfacing. Moving the cutter beneath the torch allows more areas of more teeth to be overlayed, and allows superior placement for operational feedback, such as automatic positioning and parameter correction.

Abstract: To facilitate overlay welding while securing a certain hardness of an overlaid portion and preventing welding defects, an overlay welding method for performing overlay welding on a surface P to be overlaid of a base material 50 includes a preparing step of forming a bottomed depression 51, with the surface P to be overlaid being a circumferential surface 51a thereof, and an overlaying step at which a filler material is fed toward a bottom face 51b of the depression 51, and a laser beam as a heat source is irradiated on the bottom face 51b of the depression 51 to which the filler material is fed, thereby forming an overlaid portion W reaching the surface P to be overlaid, while filling the bottom face 51b of the depression 51 with a melted filler material.

Abstract: The present invention provides a method for tandem gas metal arc welding using a leading electrode and a trailing electrode, wherein a shielding gas for the leading electrode is a two-component mixed gas containing argon and carbon dioxide, or a three-component mixed gas containing argon, carbon dioxide, and oxygen; a shielding gas for the trailing electrode is argon, a two-component mixed gas containing argon and carbon dioxide, a two-component mixed gas containing argon and oxygen, or a three-component mixed gas containing argon, carbon dioxide, and oxygen; and the concentration of carbon dioxide in the shielding gas for the trailing electrode is lower than the concentration of carbon dioxide in the shielding gas for the leading electrode.

Abstract: A welding machine that includes a machine frame having an opening permitting access to an interchangeable tooling module installed on the machine. The welding machine includes one or more light curtains covering the opening to disable operation of one or more welding stations on the tooling module if the light curtain is breached by an operator, robot, or other object. The welding machine includes a selector arm attached to the machine frame at a location between a first end and a second end of the opening. The selector arm can be moved into and out of position at the opening to selectively define either a single light curtain across the opening or a pair of adjacent light curtains that permit separate operation and access to separate welding stations behind each of the two light curtains.

Abstract: The invention relates to a device and a process for the arc welding of metal workpieces employing a MIG/MAG welding torch combined with a TIG welding torch so as to operate simultaneously and to obtain welded joints free of protruding defects.

Abstract: A welding system, welding process and welded article are disclosed. The system includes a laser welding apparatus, a GMAW apparatus, and a GTAW apparatus. The laser welding apparatus, the GMAW apparatus, and the GTAW apparatus are positioned to weld an article along a weld path. The process includes providing a welding system having a laser welding apparatus, a GMAW apparatus, and a GTAW apparatus. The process further includes welding an article with one or more of the laser welding apparatus, the GMAW apparatus, and the GTAW apparatus. The welded article includes a weld formed by welding from a GMAW apparatus, a laser welding apparatus, and a GTAW apparatus.

Abstract: A preserving apparatus for preserving welded joint portions 7, 8 by deposit welding on the inner surface of the welded joint portions 7, 8, in which a nozzle 4 and a pipe 5 supported under water are joined, the apparatus having: a seal member 9 that is disposed in front and behind the welded joint portions 7, 8 to be deposit welded within the nozzle 4 and pipe 5, and serves to demarcate and form a closed operation area A within the nozzle 4 and pipe 5; water drainage means 12 for draining the inside of the operation area A demarcated and formed by the seal member 9 and obtaining a gas atmosphere therein; and welding means 13 for deposit welding on the inner surface of the welded joint portions 7, 8 within the operation area A in which the gas atmosphere has been created.

Abstract: Methods for arc welding unalloyed or low-alloy steels with consumable electrode under protective gas are suggested, in which the protective gas is a mixture comprising at least helium and an active gas as well as a further inert gas. In the general case, the proportion of the active gas in the total volume of the protective gas is to be in the range from more than 0.5% to approximately 1.5% and the proportion of helium in the total volume of the protective gas is to be more than 30%. In case an electrode having a lowered or medium Si content of approximately 0.2% to approximately 0.4% is used, the proportion of the active gas in the total volume of the protective gas is to be approximately 1% to approximately 5%. If an electrode with a low Si content of approximately 0.05% to approximately 0.1% is used, the proportion of the active gas in the total volume of the protective gas is to be approximately 3% to approximately 10%.

Abstract: An arc system is described which includes a power generator, a shielding gas source, a torch and a shielding gas monitor contained adjacent to or within the torch. The torch is connected to the power generator for producing an arc with a workpiece, is connected to the shielding gas source for providing shielding gas to an arc locations, and includes a flow sensor mounted within or adjacent the torch body for monitoring the flow of shielding gas through the torch and optimally providing feedback control of the shielding gas flow.

Abstract: The invention relates to an electric arc welding method for welding at least one metal part including an aluminum based surface coating, using a shielding gas. According to the invention, the metal of the aforementioned metal part is melted by the electric arc alone without the use of any laser beam. The invention is characterized in that the shielding gas comprises a mixture of argon and/or helium, nitrogen, and an oxidizing compound selected from oxygen and carbon dioxide.

Abstract: A rapid change nozzle apparatus includes a nozzle member and a seat or base member wherein the nozzle member may be quickly and easily manually selectively connected with and/or detached from the seat or base member in order for maintenance personnel or operators of an associated welding system to conveniently replace the nozzle as necessary or desired without significant down-time impact relative to the underlying welding processes. The nozzle member is supported relative to the base or seat member by a set of pin members extending from the base member and received in longitudinal and circumferential grooved in the nozzle member body, and by the biasing influence of a spring member disposed between the nozzle member and the base member whereby the spring urges the nozzle member into relative separation from the base member and into contact with the locating pin members.

Abstract: The invention relates to a ternary gaseous mixture formed from argon, helium and oxygen, characterized in that it is formed from between 19.5 and 20.5% of helium, between 2.7 and 3.3% of Oi, and argon for the remainder (volume %), and to the use thereof as gaseous protection in a method of electric arc welding of at least one steel part to carbon, using a fusible filler wire. Preferably, the welded parts overlap or cover each other and the rotary arc welding takes place where the parts overlap.

Abstract: The invention relates to a hybrid laser/arc-welding method using an electric arc and a laser beam that are combined together within a single welding bath, to which molten metal is supplied by melting a filler wire, wherein the welding bath is provided on at least one steel part including an aluminum surface coating, and a protective gas is used, characterized in that the protective gas consists of at least one main compound selected from argon and helium, and of at least one additional compound selected from nitrogen and oxygen.

Abstract: The invention relates to a method for electric arc welding, without a laser beam, one or more metal parts, in particular made of steel, including an aluminum surface coating, in particular a coating consisting of aluminum and silicon, using a protective gas, characterized in that the protective gas consists of a mixture of argon and/or helium, and additionally of nitrogen, in particular less than 30 volume % of nitrogen, typically 2 to 10 volume % of nitrogen.

Abstract: Apparatus and methods convert a MIG welder into an effective cutting machine. A plug adaptor is installed into the existing MIG welder gun cup nozzle, which has an inside diameter and a length. A contact tip within the cup has an outside diameter, and shielding gas ports in the cup typically surround the contact tip. The plug adaptor comprises a body having a width dimension corresponding to the inside diameter of the cup, a length corresponding to the length of the cup, and a central bore corresponding to the outer diameter of the contact tip. A channel is established between the width dimension of the body and the inside diameter of the cup enabling air to flow from the shielding gas ports to a workpiece for slag removal produced during the cutting operation. The MIG gun is not modified in any way except for the addition of the removable adaptor.

Abstract: The present invention provides a method for tandem gas metal arc welding using a leading electrode and a trailing electrode, wherein a shielding gas for the leading electrode is a two-component mixed gas containing argon and carbon dioxide, or a three-component mixed gas containing argon, carbon dioxide, and oxygen; a shielding gas for the trailing electrode is argon, a two-component mixed gas containing argon and carbon dioxide, a two-component mixed gas containing argon and oxygen, or a three-component mixed gas containing argon, carbon dioxide, and oxygen; and the concentration of carbon dioxide in the shielding gas for the trailing electrode is lower than the concentration of carbon dioxide in the shielding gas for the leading electrode.

Abstract: The invention relates to a hybrid laser/arc-welding method using an electric arc and a laser beam that are combined together within a single welding melt to which molten metal is supplied by melting a filler wire, wherein the welding melt is provided on at least one steel part including an aluminum surface coating, and a protective gas is used, characterized in that the filler wire contains at least 3 wt % of one or more gammagenic elements, in particular the gammagenic elements selected from C, Mn, Ni and N, and the protective gas consists of helium and/or argon with the addition of at least 10 vol % of nitrogen or oxygen. The method of the invention is particularly suitable for welding end-welded flanks used in the field of manufacturing automobiles or for tube welding.

Abstract: A welding gun, including a contact tip assembly, a diffuser cap, a tip holder, and a shielding gas diffuser, where the shielding gas diffuser includes a casing and an axial tube extending within the casing, and where the casing and the tip holder are connected via a connection system that includes threads with reduced peaks.

Abstract: Disclosed is a hardfacing alloy deriving its usefulness from carbides and borides of molybdenum and niobium. The alloy does not rely on chromium as an alloying agent. The hardfacing alloy is capable of being applied to a number of industrial substrates in a crack-free manner, and once applied convert the substrate to a wear- and abrasion-resistant material having an extended service life, even when subjected to harsh wear conditions.

Abstract: An ultrahigh-strength welded joint with superior strength and toughness, and a method for producing the ultrahigh-strength welded joint by means of single-pass welding by using laser hybrid welding, are provided, wherein the welded joint comprising a steel plate having a plate thickness of 4 mm to 12 mm and including weld metal of almost full martensite structure, wherein, in a cross-section of the welded joint in a direction perpendicular to a welding direction, a cross-sectional shape of the weld metal has a width W1 of 2.0 to 7.0 mm at a surface of the steel plate and a width W2 of 0.5 to 2.4 mm at a position where is separated from the surface by three-quarters of the plate thickness, wherein the weld metal comprises, by mass %, C: over 0.09% to 0.24%; Si: 0.2% to 1.0%; Mn: 0.5% to 2.5%; P: 0.02% or less; S: 0.02% or less; Al: 0.004% to 0.08%; Ti: 0.005% to 0.15%; O: 0.005% to 0.05%; and Ni: 1.0% to 9%, and wherein a carbon equivalent (Ceq) is 0.40% to 1.

Abstract: A method and apparatus for microplasma spray coating a portion of a substrate, such as a gas turbine compressor blade, without masking any portions thereof. The apparatus includes a microplasma gun with an anode, cathode, and an arc generator for generating an electric arc between the anode and cathode. An arc gas emitter injects inert gas through the electric arc. The electric arc is operable for ionizing the gas to create a plasma gas stream. A powder injector injects powdered material into a plasma stream. A localized area of the compressor blade is coated with the powdered material without having to mask the compressor blade.

Abstract: A laser welding device for manufacturing a prismatic battery 10 of the invention has a pair of jigs 12A, 12B for securing a prismatic battery outer can B1, a gas supply section for supplying inert gas to welding points of a sealing cover B2 fitted to the prismatic battery outer can B1, and a laser unit 11 for irradiating laser beam. Each of the jigs 12A, 12B is provided with a slit-shaped blower outlet and the blower outlet is positioned below the welding points. The inert gas is supplied to the blower outlet from the gas supply section and is blown from the blower outlet to the welding points from below. The laser welding device for manufacturing a prismatic battery 10 can obtain a laser welding device that welds the sealing cover B2 fitted to the prismatic battery outer can B1 fast, preventing weld droops and allowing uniform welding.

Abstract: Some embodiments relate to an electrical contact assembly for a plasma torch tip, and may include an electrical contact portion, a compressible portion in mechanical communication with the contact, and a mounting portion in mechanical communication with the compressible portion. Some embodiments may be adapted to maintain contact with an uneven substrate during translation of the torch tip.

Abstract: A feeding lubricant for use on a welding electrode comprises about 10 to 40 wt. % of at least one soap-based lubricant, about 40 to 90 wt. % of at least one solid particulate lubricant selected from MoS2, WS2, ZnO, graphite and PTFE and up to 20 wt. % of at least one optional additional particulate lubricant ingredient.

Abstract: An air-carbon arc system for reducing irregularities in a work piece surface including a control box, a torch head operationally connected to the control box and configured to cooperate with the work piece to generate an arc, and a pendant operationally connected to the control box and having a means for reducing irregularities in the work piece surface.

Abstract: A purge plug for welding applications is provided that can be interchangeably used to seal tubing, pipes, or the like of various diameter or cross-sectional area. The purge plug has a central body with a male connector and a diffuser disposed on the end portions. The purge plug also includes one or more flexible seals annularly disposed around the central body. In some implementations, the diameter of the flexible seals is slightly larger than the diameter of the tubing or pipe. When the purge plug is inserted into the tubing or pipe, the resiliency of the seal allow the seal to expand mechanically and flex against the inner walls of the tubing, thus sealingly engage with the inner walls.

Abstract: A method of starting a plasma arc torch is provided that includes directing a pre-flow gas and a start shield gas through the plasma arc torch during generation and transfer of a plasma arc, and switching from the pre-flow gas to a plasma gas, and switching from the start shield gas to a primary shield gas after transfer of the plasma arc to a workpiece. A method of stopping a plasma arc torch is also provided that includes directing a plasma gas and a primary shield gas through the plasma arc torch during steady-state operation, and switching from the primary shield gas to a stop shield gas during ramp down of an operating current.